Wireless Power Receiver Circuitry Duty Cycle Limiting
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Solution Overview
Problem
Current wireless power transfer systems face inefficiencies in power coupling over distance and interference issues, and are limited in charging multiple devices simultaneously due to the need for close antenna spacing, leading to undesirable 'darkside operation' where power transfer degrades significantly.
Innovation Solution
The implementation of a wireless power transfer system using near-field coupling between a transmitter and receiver with loop antennas, where the resonant frequency of both is matched to minimize transmission losses, and active circuitry on the receiver side to limit pulse width modulation duty cycle and prevent 'darkside operation by maintaining input voltage above a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If plane wave radiation coupling is used between transmit and receive antennas, then power can be transmitted over distance, but power coupling efficiency falls off quickly with distance making charging >1-2m difficult
Solution Approach 1:
The patent changes the operating parameters by using resonant frequency matching between transmit and receive loop antennas. This resonance condition creates strong magnetic coupling that maintains efficient power transfer over distances significantly greater than traditional inductive coupling, directly addressing the efficiency-distance tradeoff
2Quantity of substance
If inductive coupling between transmit and receive antennas is used, then multiple devices can be charged simultaneously, but spacing between antennas must be very close (mms)
Solution Approach 1:
The patent uses resonant frequency matching to enhance the coupling coefficient between antennas, allowing multiple devices to be charged simultaneously at practical spacing distances. The resonance condition creates a distributed magnetic field that can accommodate multiple receivers without requiring millimeter-scale proximity
3Length of stationary object
If plane wave radiation is used for wireless power transmission, then charging can occur at reasonable distances, but unintentional radiation interferes with other systems requiring filtering
Solution Approach 1:
The patent confines the electromagnetic energy primarily to the near-field magnetic coupling region through resonant loop antennas. This localized field confinement prevents far-field radiation and interference with other systems while maintaining effective power transfer at charging distances, eliminating the need for extensive filtering
4Power
If power converter duty cycle is not limited in wireless power receiver, then power transfer can be maximized, but undesirable darkside operation occurs where power transfer degrades significantly
Solution Approach 1:
The patent implements a feedback mechanism that monitors the duty cycle of the power converter and applies limiting when approaching darkside operation conditions. This feedback control maintains power transfer within a stable operating range, preventing the degradation associated with darkside operation while maximizing efficient power transfer
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances power transfer efficiency over distance, allows for simultaneous charging of multiple devices, and prevents the degradation of power transfer seen in 'darkside operation, ensuring stable and efficient energy delivery.
Implementation Method 1
The implementation of a wireless power transfer system using near-field coupling between a transmitter and receiver with loop antennas
Implementation Method 2
where the resonant frequency of both is matched to minimize transmission losses
Data Source
AI summary
Exemplary embodiments are directed to wireless power receivers. A device may include a power converter configured to receive an input voltage. The device may further include circuitry configured to limit a pulse width modulation duty cycle of the power converter to prevent the input voltage from dropping below a threshold voltage.